Method of shaping a continuous glass tube



N. MOREAU ET AL METHOD OF SHAPING A CONTINUOUS GLASS TUBE Sept. 5, 19677 Sheets-Sheet 1 Original Filed Oct. 2'7. 1960 INVENTORa N lV0RMflNNa/eEflu 4/1/0 (70 lY/Y Ads/PERT Sept. 5, 1967 N. MOREAU ET AL 3,340,033

METHOD OF SHAPING A CONTINUOUS GLASS TUBE Original Filed Oct. 2'7, 19607 Sheets-Sheet 2 lNVENTOR Sept. 5, 1967 N, MOREAU ET AL METHOD OFSHAPING A CONTINUOUS GLASS TUBE Original Filed Oct.

'7 Sheets-Sheet INVENTORS fl a/P/ m/v MORE/9U JON/v 4- 551F587 Sept. 5,1967 N. MOREAU ET AL METHOD OF SHAPING A CONTINUOUS GLASS TUBE '7Sheets-Sheet 4 Original Filed Oct. 27, 1960 Sept. 5, 1967 N. MOREAU ETAL METHOD OF SHAPING A CONTINUOUS GLASS TUBE 7 Sheets-Sheet 5 OriginalFiled Oct. 27, 1960 LN R O E M2 50/ M N. m4 N m @w D N A m- Sept. 5,1967 MQREAU ET AL 3,340,033

METHOD OF SHAPING A CONTINUOUS GLASS TUBE Original Filed Oct. 27. 1960 7Sheets-Sheet 6 I8 I I7 Sept; 5,, 1967 N, MQREAU ETAL 3,340,033

METHOD OF SHAPING A CONTINUOUS GLASS TUBE Original Filed Oct. 27. 1960 7Sheets-Sheet 7 NUMBER 0/ I701 05 MOLD Cf/A/IV LENGTH INVENTORS /l/a EMA/v Ware/SA u n/vo Jon/v 4. SE/AE'ET United States Patent M 3,340,033METHOD OF SHAPING A CONTINUOUS GLASS TUBE Norman Moreau, Lincoln, andJohn A. Seifert, East Providence, R.I., assignors to Corning GlassWorks, Corning, N.Y., a corporation of New York Application Oct. 29,1964, Ser. No. 414,047, now Patent No. 3,245,773, dated Apr. 12, 1966,which is a divison of application Ser. No. 65,339, Oct. 27, 1960, nowPatent No. 3,181,941. Divided and this application Oct. 19, 1965, Ser.No. 497,835

4 Claims. (Cl. 65-87) This application is a division of our application,Ser. No. 414,047, nowPatent No. 3,245,773, filed on Oct. 29, 1964, whichis, in turn, a division of our application, Ser. No. 65,339, filed onOct. 27, 1960, now United States Patent 3,181,941.

The present invention relates to a method of and apparatus for modifyingthe form of glass tubing while traveling from a source of formationtoward a delivery position.

It has been discovered that tubular electric lamps, of greatly increasedefiiciency, can be obtained by imparting to their envelopes aconfiguration in which the perimeterto-area ratio is greater than thatof round tubes of like cross sectional area, and that such tubes havegreater strength and higher resistance to implosion than simpleflattened tubes. Preferred forms of such a tubular electric lamp arefully shown and described in United States Patent No. 2,915,664. Apresently known method of and apparatus, respectively, for reformingindividual glass tubes in the production of such lamps are disclosed inUnited States Patents Nos. 2,862,337 and 2,862,335.

According to the invention a tubular stream of molten glass issuing froma tube making forehearth and traveling toward a delivery position is,near its source, encircled with embracing members or cylindrical moldshaving passages through the walls thereof. Cams along the common path oftravel of the stream and molds project tools through such passages tomodify the form of the tubing in a desired manner. Before the path oftravel of the molds divert from that of the tubular glass stream suchtools are withdrawn and such molds separated to permit the tube tocontinue uninterruptedly on its course. In the meantime the molds returnto position for subsequent embracement of the oncoming tubing.

For a full understanding of the invention reference is made to theaccompanying drawings.

In the drawings, FIGS. 1 and 1a together comprise a plan view, partly insection, of a machine embodying the invention.

FIG. 2 is a view of a fragment of the machine, partly in section, asseen when looking in the direction indicated by arrows 22 in FIG. 1.

FIG. 3 is a view of the machine as seen when looking in the directionindicated in FIG. 1 by arrows 33.

FIG. 4 is a top plan view, on an enlarged scale and partly in section,of the chain of molds and of sprocket wheels about which the chains aretrained.

FIG. 5 is a side elevational view of part of one of the chains with someof the molds shown and with mold halves completing an end turn about oneof the sprocket wheels.

FIG. 6 is a sectional view taken on line 66 of FIG. 5.

FIGS. 7 and 8 are similar cross sectional views of other forms of moldsemployed.

'FIG. 9 is a diagrammatic view showing the machine in association with ahorizontal tube drawing forehearth and a tube drawing tractor.

FIG. 10 is a straight line diagram illustrating the com- Patented Sept.5, 1967 'bination of chain supported molds in the machine asillustrated.

As will be observed from FIGS. 1, 1a and FIG. 3, a carriage 16 hasarranged thereon endless chains 17 and 18 trained about drive sprocketwheels 21 and 22 and about idler sprocket wheels 24 and 25 respectively.Sprocket wheels 21 and 22 are suitably keyed to a shaft 23 driven by amotor 26 through the medium of a belt 29, a speed regulating unit 30, abelt 31, a speed reducing unit 32 and a bearing 33.

The chains 17 and 18, which between their sprocket wheels ride on railssuch as 46 (FIGS. 1 and 3), carry the respective halves of axially splitmolds such as molds 35, 36 and 37, best illustrated in FIGS. 6, 7 and 8,respectively. As will be seen from FIGS. 4 and 5 the mold halves on theone side of their center line are axially shifted with respect to theirmating halves on the other side. This is done owing to the staggeredarrangement of the indentations to be made in opposite sides of thetubing. These molds comprise mold halves such as 38 and 39 (FIG. 7) eachhaving a bracket such as 41 or 43 pivoted about a pin such as 40 passingthrough a chain supported mold mounting bracket such as 49 or 50 andeach mold half having a roller such as 42. Springs such as 44 or 45 biasthe mold halves to their open positions as shown in FIG. 2. To close themold halves about the tubing as their path of travel joins that of thetubing there are provided cam tracks 47 and 48 (FIGS. 2 and 3)engageable by their rollers such as 42.

Cam tracks 47 and 48 are mounted on suitable upright guide posts 51 and52 respectively and are held in properly adjusted positions by lockingscrews such as 53. To facilitate adjustment of cam tracks 47 and 48,they are provided with slots into which bell cranks such as 55 areprojected. These bell cranks are pivoted as at 57 and are turned abouttheir pivots by means of adjusting screws such as 63. When the properpositions of the cam tracks have been established the screws such as 53are tightened.

Blank molds such as 37 (FIG. 8) serve as spacers and simply embrace thetubing along lengths thereof wherein no reforming of the tubing is to beeffected, there being a number of these molds determined by the lengthof plain tubing it is desired to have between the respective reformedsections thereof.

Adjoining each end of a row of molds such as 37 is a mold 36, as shownin FIG. 7. Such a mold is provided with plungers 65 and 66 for reformingthe tubing in a manner to form mercury pockets therein as required ateach end of a fluorescent tube.

Each plunger such as 65 or 66 is locked against turning about the axisof its supporting slide rod such as 68 by a key such as 69 pressed intoa groove in such rod and slidable in a groove such as 70 (FIG. 8) in abracket such as 73 attached to the mold half and occupied by rod 68. Inand out movement of a plunger is accomplished by means of an actuatorpin 71 passing through a slot in bracket such as 73 and threaded intorod 68. Pin 71 is straddled by the end of an actuator arm such as 72 asbest shown in FIG. 4. The arms such as 72 are pivoted as at 75 and carryoperating rollers such as the roller 76. As best illustrated in FIGS. 1and 2 cam tracks 81 and 82 are arranged for engagement of the rollerssuch as 76 while a mold embraces the tubing. Cam tracks 81 and 82 aremounted on suitable transverse slide ways such as 85 and are laterallyadjustable by means of screws such as 87. The molds such as 35 ('FIG. 6)are identical to those such as 36 except for the difference in theirplunger shape.

Before a mold arrives at the end of its travel with the tubing therollers such as 76 travel off the end of the cam tracks 81 and 82 andencounter plunger pull out cams 88 (FIG. 1) and 89, mounted on brackets93 and 94, respectively, and which withdraw the plungers fromassociation with the tubing before the mold arrives at the region ofsprocket wheels 21 and 22 and start to be separated from one anotherunder the influence of springs such as 44 and 45 as the rollers such as42 become disengaged from cam tracks 47 and 48.

Referring now to FIG. 9 a forehearth 90 has been shown having a tubularstream 91 of glass issuing therefrom being horizontally drawn by atractor 92, but which may be dispensed with while employing applicantsforming machine. As the tubing passes through such machine therespective molds close thereabout and the tubing is formed with pocketswhile embraced with molds such as 35 and 36 in a manner clear from thepreceding description.

Referring now to FIG. 10, it will be seen that in the particularembodiment of the invention illustrated, there is a series of nineteenmolds such as 35 flanked on either side by a mold 36, with the spacebetween molds 36 separated by ten blank molds 37. There will accordinglybe one section of tubing formed for each complete cycle of travel of thechains 17 and 18.

Although the invention is illustrated as applied to horizontal drawingof tubing, it obviously is not limited to such use, since if desired,the machine may equally well be mounted vertically and fed with tubingeither from an updraw or a down-draw source without departing from theinvention as described and hereinafter claimed. Moreover, although atractor is illustrated as used as is common practice in drawing tubing,it will be appreciated that applicants machine is itself a tractor andmay be so employed in the drawing of tubing horizontally or vertically;and that when used with a down-draw system may even be employed in amanner to counteract the tendency of acceleration of rate of drawotherwise resulting from the weight of the pendant glass tubing issuingfrom such a system.

We claim:

1. The method of modifying the shape of a tubular body of heat-softenedthermoplastic material during its travel from a source to a deliveryposition, which comprises the steps of circumferentially embracing aportion of said body, pressing a part of said portion inwardly whilesaid part is in a heat-softened state to form an inwardly projectingwall portion in said tubular body, and subsequently removing saidportion from such embracement.

2. The method of modifying the shape of a tubular body of heat-softenedglass during its travel from a source to a delivery position, whichcomprises the steps of embracing a portion of said body alongsubstantially its entire circumference in the vicinity of each end ofsaid portion while embracing an intermediate part of said portion alongsubstantially less than its entire circumference, pressing a part ofsaid portion inwardly while said part is in a heatsoftened state to forman inwardly projecting wall portion in said tubular body, andsubsequently removing said portion from such embracement.

3. The method according to claim 2 which includes embracing a pluralityof portions of said body and pressing inwardly a plurality of saidunembraced parts spaced along said body alternately on opposite sidesthereof.

4. The method of modifying the shape of a tubular body of heat-softenedglass during its travel from a source to a delivery position, whichcomprises the steps of embracing a portion of said body in a cylindricalmold having a passage therethrough, passing a tool through said passageand thereby pressing a part of said portion inwardly while said part isin a heat-softened state to form an inwardly projecting Wall portion insaid tubular body, removing said tool from said passage, and removingsaid portion from said mold prior to arrival of said portion at saiddelivery position.

References Cited UNITED STATES PATENTS 1,952,470 3/1934 Stephens 264-177X 2,417,165 3/1947 Jacobson 18l4 2,802,530 8/1957 Kaufman 264156 XDONALL H. SYLVESTER, Primary Examiner. A. D. KELLOGG, AssistantExaminer.

2. THE METHOD OF MODIFYING THE SHAPE OF A TUBULAR BODY OF HEAT-SOFTENEDGLASS DURING ITS TRAVEL FROM A SOURCE TO A DELIVERY POSITION, WHICHCOMPRISES THE STEPS OF EMBRACING A PORTION OF SAID BODY ALONGSUBSTANTIALLY ITS ENTIRE CIRCUMFERENCE IN THE VICINITY OF EACH END OFSAID PORTION WHILE EMBRACING AN INTERMEDIATE PART OF SAID PORTION ALONGSUBSTANTIALLY LESS THAN ITS ENTIRE CIRCUMFERENCE, PRESSING A PART OFSAID PORTION INWARDLY WHILE PART IS IN A HEATSOFTENED STATE TO FORM ANINWARDLY PROJECTING WALL POR-